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Monday, October 24, 2005
What a horrible month it's been. And there's chem prac tomorrow. Yeah, sure I remember all the shit we're supposed to learn, but I'm worried I won't be able to finish on time. Stupid VA. I actually dropped the friggin pipette into the conical flask and had to do the whole thing again cos of accuracy and that kinda crap.
Maybe single science would have been a better choice? I mean, all the single science-ers at school are all so happy, like, all the time. And they're all so united, even though their class is the smallest.
...But then I'd have to count BOTH geog and Combined Humanities. What a horrible thought. I hate geog. Yeah, what was I thinking two years ago? Who wouldn't think Shakespeare is less interesting than rift valleys. Darn it, my stupid decision has come back to bite me on the ass.
To make me feel less guilty about using the comp, let's go through chem! Yeah, there's the NaOH test for cations, white precipitate which dissolves can be Zn2+, Al3+, or Pb2+, and if it's undissolvable it's Ca2+. And if nothing happens you'd better get your litmus out cos it's most probably NH4+. If you get a blue solution there'll be some blue precipitate that won't dissolve (I think), which most likely makes it copper. A green one will produce a "dirty green" precipitate, which is Fe2+, and a yellow one will form a red one (like curry!), which means it's probably Fe3+.
Then there's the uh...aqueous NH3 or NH4OH test. Calcium with have no visible reaction, zinc's white precipitate will dissolve but aluminium and lead's won't. It's the same for iron 2 or 3, but the blue precipitate for Cu will "dissolve to give a dark blue solution". Is it that one? Or is that for NaOH? Never mind, I'll find out when I do it.
Then there are all the anion tests. Might as well go through them all. Hm...starting in alphabetical order. Carbonates. We can add some barium nitrate to it, which will give a white ppt, and when dilute HNO3 is added the ppt will dissolve with a lot of bubbling, which is really cool. Then there's the chlorides, where you add silver nitrate followed by more dilute nitric acid, and you'll get a white ppt. For iodides it's the same, only you'll get a yellow ppt. For nitrates you add some NaOH, some aluminium powder/Devarda's alloy, heat, then stick a red litmus and a lighted splint into the test tube to see if you're getting the correct gases. And lastly sulphates. Test is the same as carbonates, only the ppt won't dissolve.
Think that's it. Please note: these notes might not necessarily correct; I'm only repeating what I learn from my own notes, so please do not come to me complaining that I made you fail, because no one asked you to copy off this blog. And anyway, there's no knowing where the QA's going...
Must go and study some more...
Maybe single science would have been a better choice? I mean, all the single science-ers at school are all so happy, like, all the time. And they're all so united, even though their class is the smallest.
...But then I'd have to count BOTH geog and Combined Humanities. What a horrible thought. I hate geog. Yeah, what was I thinking two years ago? Who wouldn't think Shakespeare is less interesting than rift valleys. Darn it, my stupid decision has come back to bite me on the ass.
To make me feel less guilty about using the comp, let's go through chem! Yeah, there's the NaOH test for cations, white precipitate which dissolves can be Zn2+, Al3+, or Pb2+, and if it's undissolvable it's Ca2+. And if nothing happens you'd better get your litmus out cos it's most probably NH4+. If you get a blue solution there'll be some blue precipitate that won't dissolve (I think), which most likely makes it copper. A green one will produce a "dirty green" precipitate, which is Fe2+, and a yellow one will form a red one (like curry!), which means it's probably Fe3+.
Then there's the uh...aqueous NH3 or NH4OH test. Calcium with have no visible reaction, zinc's white precipitate will dissolve but aluminium and lead's won't. It's the same for iron 2 or 3, but the blue precipitate for Cu will "dissolve to give a dark blue solution". Is it that one? Or is that for NaOH? Never mind, I'll find out when I do it.
Then there are all the anion tests. Might as well go through them all. Hm...starting in alphabetical order. Carbonates. We can add some barium nitrate to it, which will give a white ppt, and when dilute HNO3 is added the ppt will dissolve with a lot of bubbling, which is really cool. Then there's the chlorides, where you add silver nitrate followed by more dilute nitric acid, and you'll get a white ppt. For iodides it's the same, only you'll get a yellow ppt. For nitrates you add some NaOH, some aluminium powder/Devarda's alloy, heat, then stick a red litmus and a lighted splint into the test tube to see if you're getting the correct gases. And lastly sulphates. Test is the same as carbonates, only the ppt won't dissolve.
Think that's it. Please note: these notes might not necessarily correct; I'm only repeating what I learn from my own notes, so please do not come to me complaining that I made you fail, because no one asked you to copy off this blog. And anyway, there's no knowing where the QA's going...
Must go and study some more...